Apparatus for extruding plastic tubes with cross-ribbed surfaces



July 30. 1968 l. s. HOUVENER 3,394,433 APPARATUS FOR EXTRUDING PLASTICTUBES WITH v CROSS-RIBBED SURFACES Original Filed Sept. 27, 1961' 2Sheets-Sheet 1 INVENTOR.

IRVING 5. HOUVENER 3,394,433 ITH 2 Sheets-Sheet 2 NER LASTIC TUBES wBBED SURFACES y 30. 1968 l. s. HOUVE APPARATUS FOR EXTRUDING P CROSS-RIOriginal Filed Sept. 27, 1961 /R V/NG S HOUVE/VER BY J I 4 g v 4 Q .r 3

United States Patent ABSTRACT OF THE DISCLOSURE Plastic tubes withcross-ribbed surfaces are made by simultaneously extruding a tube. andcross-ribbing through rotating nozzle. pieces arranged concentrically.

This application is a continuation application of copending applicationSer. No. 141,163, filed Sept. 27, 1961 and nowabandoned.

This invention relates to an apparatus adapted for fabrication oftubular webbing, which, if desired, may be formed on the exteriorsurface of a tubular film, to enhance its appearance and strength.

While any material which is extrudable may be used in practicing theinvention, plastic materialssuch as normally solid polyolefins,particularly polyethylene, polypropylene, copolymers of ethylene andpropylene and the like, polystyrene and nylon, may be mostadvantageously utilized.

The type of product under consideration is relatively new in the art ofplastic extrusion. For example, reference may be made to US. Patent2,919,467 issued Jan. 5, 1960, to F. B. Mercer, which discloses a methodand apparatus for fabrication of plastic net-like structures. While theteachings of the Mercer patent and those of the present disclosure, havecertain objectives in common, the method, apparatus and productdisclosed herein differ signifi cantly from that of the Mercer patent.Considering the product, that produced by the apparatus of Mercer isobtained in effect, by longitudinally splitting or shearing extrudedstrands of material as they move from an extrusion nozzle. Predeterminedlengths .of each strand are left unsplit whereby adjoining strands willbe interconnected in a manner as to form a net-like structure.

In the product produced by the apparatus of the present invention, thestrands making up the web-like structure are extruded with a uniformthickness diameter and in a predesignated manner to achieve a web-likeproduct. Irrespective of the relative merits of the comparative productsunder consideration, the principles of the present in- Vention providegreater flexibility in product, for among other things, either tubularwebbing or tubular film having a web-like exterior, may be extruded in acontinuous operation. The apparatus of the present invention maylikewise be used to achieve a great variety of web patterns, as with theapparatus of the Mercer patent.

An object of this invention is to provide apparatus for producingwebbing in a continuous extrusion operation.

Another object of the invention is to provide apparatus for producingplastic webbing in a continuous extrusion operation wherein the patternof the webbing may be varied.

Still another object of the invention is to provide apparatus forproducing a plastic tubular product in either webbing form, or as asolid film having an integrally formed webbing exterior surface.

These and further objects and features of the invention will become moreapparent from the following description and accompanying drawingswherein:

FIG. 1 is an elevation view in cross section of another ice embodimentof extruder apparatus embodying the principles of the invention;

FIG. 2 is a section view generally as seen along line 77 in FIG. 1; and

FIG. 3 is an exploded view of certain components forming a rib formingnozzle assembly used in the apparatus of FIG. 1.

Referring now to the drawing, the extruder head assembly includes acylindrical inner tube forming nozzle 92, which is secured to acomposite piece 94 comprising an outer tube forming nozzle 96, and abearing cap 98. A generally cylindrical body member is secured at oneend to the bearing cap 98 by fastening means, such as cap screws 102. Abearing cap 104 is secured to the other end of the body member 100 byfastening means, such as cap screws 106. The body member 100 has aconcentrically arranged cylindrical portion 108 supported by a web 110which extends the full circumference of the body member except for aportion which provides clearance for a bevel gear 112, mounted upon theend of a drive shaft 114. An outboard bearing is provided in thecylindrical portion 108 for the gear 112.

Portions of the outer wall of the inner tube forming nozzle 92 as wellas the inner wall of the outer tube forming nozzle 96 are recessed toprovide a material conduit 116 extending about the entire circumferenceof the nozzle and tapering in the direction of the bearing cap 104.

An inner ribnozzle piece 118, generally cylindrical in form and having aflange 120 at one end, is mounted for sliding engagement relative tovarious components including the composite piece 94, the end surface ofthe cylindrical portion 108, as well as the inner surface of the bodymember 100. A ring gear 122, affixed to the flange 120 by fasteningmeans, such as cap screws 125, is arranged for driven engagement by thebevel gear 112.

An outer rib nozzle piece 124, which is generally cylindrical in form,is mounted for sliding engagement relative to various componentsincluding the bearing cap 104, a surface of the cylindrical portion 108,as well as the inner surface of the body member 100. A ring gear 126,affixed to the nozzle piece 124 by fastening means such as cap screws128, is arranged for driven engagement by the bevel gear 112.

An inner rib forming material conduit is provided on an inner portion ofnozzle piece 118 and extends about the entire circumference thereof. Thelower end of the nozzle piece 118 has a conical inwardly taperingportion 132, the inner surface having a plurality of radially arrangedinner rib-forming grooves 134, the upper ends of which open into thematerial conduit 130. An outer rib forming material conduit 136 isprovided on an inner portion of the nozzle piece 124 and extends aboutthe entire circumference thereof. The lower end of the nozzle piece 124has a conical inwardly tapering portion 138, the inner surface having aplurality of radially arranged outer rib forming grooves 140, the upperends of which open into the material conduit 136. It will be noted thatthe inner surface of the tapering portion 132 is in sliding engagementwith a conical tapered surface 142 provided on the lower end of thenozzle 96, while the inner surface of the tapering portion 138 is insliding engagement with the exterior surface of the conical taperingportion 13-2. The lower extremities of the tapering portions 132 and138, as well as the nozzle end 142, terminate in substantially the sameplane so that material being extruded from the material conduits 116,130 and 136 will emerge generally simultaneously from the extruder headassembly 90.

Gate means in the form of a circumferential groove 144, 146 and 148, areprovided in the cylindrical portion 108. Gate 114 is in communicationwith supply conduit 116 via a plurality of radially arranged flowcontrol chan- 3. nels 150, formed in the nozzle piece 118, acircumferentially arranged transfer groove 152, and a plurality ofradially arranged flow control channels 154. The groove 152 and channels154 are formed in the nozzle 96. Gate 146 is in communication withmaterial conduit 130 via a plurality of radially arranged flow controlchannels 156 formed in the nozzle piece 118. Gate 148 is incommunication with material conduit 136 via flow control channels 158formed in the cylindrical portion 108. Attention is directed to the factthat the gates 144, 146, and 148 have an eccentric configuration, sothat the depth tapers to a point of minimum dimension.'In such manner, apressure distributing means is provided for plastic material forced intothe gate so that it will flow evenly during an extrusion operation.

Material is fed to the gates 144, 146 and 148 by conduit, or passageways160, 162, and 164, respectively, all of which are formed in thecylindrical portion 108 and web 110. The conduits 160, 162 and 164, areadapted for connection to pipe means leading from a source(s) ofpressurized material to be extruded by the head assembly 90. While theconduits may variously be arranged relative to the exterior pipe means,conduit 160 is shown being served by a pipe 166, while conduits 162 and164 are shown as being served by a pipe 168. Such variation in conduitconnect-ion possibilities provides for extrusion of a tubular film 170with exterior ribs 172 and 174, all being .of the same material, or withdifferent combinations of material. For example, the material used forextruding the tubular film 170 may be a plastic of a given color, whilethe material used for extruding the exterior ribs 162 and 174 may befiber reinforced and of different color.

The operation of the extruder head assembly 90 should be apparent,however, briefly it is as follows. Plastic material is forced underpressure from the lower ends thereof. The material emerging from theconduit 116 will form a solid tubular film 170, while that emerging fromthe material conduits 130 and 136 will form a helical crisscross patternof ribs 172 and 174 on the exterior wall of film 170. The pattern of theribs 172 and 174 will depend upon various factors including the numberof grooves 134 and 140, the relative speed of rotation between thenozzle pieces 118 and 124, and the material extrusion irate. Althoughthe gearing arrangement shown will give a uniform helical rib pattern,individual drives may be arranged for the ring gears to provide variedpatterns when the ring gears are rotated in controlled directions.

It may be desirable to provide pressurized gaseous medium or coolingfluids to the inside of the tubular film 170 as it is being extruded.Toward this end, such medium may be introduced through the tube formingnozzle 92. Attention is. directed to the fact the web-like tubularforms, i.e., ribs 172 and 174, may be extruded independent of a solidtubular film, i.e., 170, by either eliminating the material conduit 116,or by shutting off supply of plastic material thereto.

'From. the foregoing it will be realized that either of the twodisclosed embodiments will satisfy the objectives of the invention setforth here-inbefore.

The foregoing description has been given in detail without thought oflimitation since the inventive principles involved are capable ofassuming other forms without departing from the spirit of the inventionor the scope of the following claims.

What is claimed is:

1. A method of fabricating a plastic tubular film having a cross ribbedsurface comprising the steps of, simultaneously extruding a plurality ofribbons of plastic material axially from equally spaced points alongconcentrically arranged circles, causing rotational movement between theribbons of one circle relative to the ribbons of the other circle,allowing the ribbons of one circle to unite with the ribbons of theother circle at each point of intersection thereof to form a tubularwebbing, forming a tube of plastic material concentric with said tubularwebbing, and causing the tubular webbing to intimately adhere to thetube of plastic material as the latter is being formed.

2. Apparatus for continuously extruding plastic tubular film having across ribbed surface including, a circular inner tube forming nozzle, acircular outer tube forming nozzle, said outer tube forming noulesurrounding the inner tube forming nozzle, a circular inner rib nozzlepiece surrounding the outer tube forming nozzle, a circular outer ribnozzle piece surrounding the in ner rib nozzle piece, said inner tubeforming nozzle and said outer tube forming nozzle being arranged toprovide a material conduit which opens at the lower end, said inner ribnozzle piece being formed with rib forming grooves on its inner wallwhich-grooves open at their lower end, said outer rib nozzle piece beingformed with rib forming grooves on its inner wall which grooves open attheir lower end, said material conduit opening and said groove openingsbeing arranged generally in the same horizontal plane, means to providerelative rotary movement between the inner rib nozzle piece and theouter rib nozzle piece, and means for conduction of plastic material tosaid material conduit and said grooves.

3.. Apparatus for continuously extruding plastic tubular film having across ribbed surface including, a circular inner tube forming nozzle, acomposite piece having a circular outer tube forming nozzle and an upperbearing cap, said outer tube forming nozzle surrounding the inner tubeforming nozzle, a circular inner rib nozzle piece surrounding the outertube forming nozzle, a circular outer rib nozzle piece surrounding theinner rib nozzle piece, said inner tube forming nozzle and said outertube forming nozzle being arranged to provide a material conduittherebetween which opens at the lower end, said inner rib nozzle piecebeing formed to provide a material conduit on its inner wall which opensat the lower end, saidouter rib nozzle piece being formed to provide amaterial conduit on its inner wall which opens at its lower end, saidmaterial conduit openings being arranged generally in the samehorizontal plane, a cylindrical body member aflixed to said upperbearing cap and surrounding the inner rib forming nozzle and the outerrib forming nozzle, a lower bearing cap affixed to the cylindrical bodymember,-a ring gear connected to the inner rib forming nozzle, a bevelgear arranged in driving relationship with both ring gears, andconduction means for conduction of plastic material to said materialconduits.

4. Apparatus according to claim 3 wherein the lower part of the materialopening between the outer film forming nozzle and the inner rib formingnozzle, as well as the lower part of the material opening between theinner rib forming nozzle and the outer rib forming nozzle are taperedinwardly toward the inner tube forming nozzle.

5. Apparatu according to claim 3 wherein the cylindrical body member isformed to include a plurality of gates and passageways forming part ofsaid conduction means.

6. Apparatus according to claim 3 wherein the tapered parts of the innerrib forming nozzle and the outer rib forming nozzle are formed toprovide radially directed grooves. 1

7. A method for fabricating tubular webbing comprising the steps ofsimultaneously extruding a plurality of ribbons of raw material in fluidform axially from equally spaced points along concentricallyarrangedcircles, causing rotational movement between the ribbons of onecircle relative to the ribbons of the outer circle, and allowing theribbons of one circle to unite with the ribbons of the other circle ateach point of intersection thereof to form a tubular webbing.

8. A method for fabricating tubularwebbing co'mpri'sing the steps offeeding raw material in fluid form to separate passage means,simultaneously extruding a plurality of ribbons of such material fromeach passage means axially from equally spaced point alongconcentrically arranged circles, causing rotational movement between theribbons of one circle relative to the ribbons of the other circle, andallowing the ribbons of one circle to unite with the ribbons of theother circle at each point of intersection thereof to form a tubularwebbing.

9. A method of fabricating a plastic tubular film having a cross-ribbedsurface comprising the steps of feeding a raw material in fluid forminto separate passage means, simultaneously extruding a plurality ofribbons of such material from each passage means axially from equallyspaced points along concentrically arranged circles, causing rotationalmovement between the ribbons of one circle relative to the ribbons ofthe other circle, allowing the ribbons of one circle to unite with theribbons of the other circle at each point of intersection thereof toform a tubular webbing, forming a tube of plastic material concentricwith said tubular webbing and causing the tubular webbing to intimatelyadhere to the tube of plastic material as the latter is being formed.

10. Apparatus for extruding tubular webbing comprising a tubular nOZZlepiece, a circular inner ribbed nozzle piece with rib forming groovestherein surrounding said tubular nozzle piece, a circular outer ribbednozzle piece with rib forming grooves therein surrounding said innerribbed nozzle piece, said tubular nozzle piece, and said grooves of saidinner ribbed nozzle piece and said outer ribbed nozzle piece beingarranged to provide material conduits which open at the lower end, saidmaterial conduit openings being arranged generally in the samehorizontal plane, means to provide relative rotary movement between theinner ribbed nozzle piece and the outer ribbed nozzle piece and meansfor conduction of raw material in fluid form to said material conduits.

11. Apparatus for extruding tubular webbing comprisging a tubular nozzlepiece, a circular inner ribbed nozzle piece surrounding said tubularnozzle piece, a circular outer ribbed nozzle piece surrounding saidinner ribbed nozzle piece, said tubular nozzle piece, said inner ribbednozzle piece and said outer ribbed nozzle piece being arranged toprovide material conduits which open at the lower end, said materialconduit openings being arranged generally in the same horizontal plane,said inner ribbed nozzle piece and said outer ribbed nozzle piece eachhaving a plurality of radially arranged rib-forming grooves at saidmaterial conduit opening, means to provide relative rotary movementbetween the inner rib nozzle piece and the outer ribbed nozzle piece,and means for conduction of raw material in fluid form to said materialconduits.

12. A tube of solid polyolefin film with an integrally formed webbingexterior surface, parallel strands of said webbing exterior surfacehaving a different physical characteristic than the parallel strandswhich are angular thereto.

13. A tube of solid polyolefin film with an integrally formed webbingexterior surface, parallel strands of said webbing exterior surfacehaving a different color characteristic than the parallel strands whichare angular thereto.

14. A tube of solid polyolefin film of one color with an integrallyformed webbing exterior surface, the parallel strands of said webbingexterior surface having a second color and the parallel strands whichare angular thereto having a third color.

References Cited UNITED STATES PATENTS 3,082,484 3/1963 Sherman.3,184,358 5/1965 Utz. 3,193,604 7/1965 Mercer 264- WILLIAM J.STEPHENSON, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,394,433 July 30 1968 Irving S. Houvener It is certified that error appearsin the above identified patent and that said Letters Patent are herebycorrected as shown below: Column 2, line 8, "drawing" should readdrawings Column 3, line 36, after "from" insert a source via pipes 166and 168 into the gates 144,146 and 148. It then move downwardly in thematerial conduits 116, 130 and 136, where it is extruded from lines 58,59 and 60 cancel "From the foregoing it will be realized that either ofthe two disclosed embodiments will satisfy the objectives of theinvention set forth hereinbeforel.

Signed and sealed this 2nd day of December 1969.

(SEAL) Attest WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

